HIV infection is a disease which ranges in clinical manifestations from asymptomatic to AIDS. It is believed that most patients, if not all, will eventually die from this disease unless an effective therapy is discovered. This study will evaluate the safety, tolerability & biologic activity of L-697,661 in 3 oral doses as compared to AZT, as standard therapy in HIV symptomatic sero-positive individuals with T-cell counts of between 200-500.